Liquid indicator



Dec. 24, 1N957 v A. wlTTLlN '2,817,309 LiQUID INDICATOR u Filed Feb. 21. 1956 United States Patent O F LIQUID INDICATOR Albert Wittlin, Chicago, Ill.

Application February 21, 1956, Serial No. 566,850

9 Claims. (Cl. 116-117) 'I his invention relates to a uid indicator adapted to be inserted in a uid `line for observing the condition of the fluid owing therethrough.

The indicator of this inventionprovides a protective member housing, a transparent tube, and sealing means seahng each end portion of the tube to the protective member so that the uid owing through the indicator will flow through the transparenttube. The protective member is provided with a viewing port by means of which the Huid owing through the transparent tube is viewable. l (.)ne of the features of this invention is that the fluid indicator is extremely compact and simple in construction so that it occupies only a verysmall space in the fluid system. This is extremely important when the indicator is used in its preferred environment, whichis in the liquid refrigerant line of a refrigeration system, as the indicator of this invention takes up very little space, yet gives a clear, unobstructed view of the uid in the liquid refrigerant line. Thus, when the indicator is used in a refrigeration system, one end `of the indicator can be attached directly if desiredto the receiver for the liquid refrigerant without requiring an interposed coupling or piping system. This is true becausey the protective member itself is so designed as to be constructed like a fitting with the usual threads or other attaching means for attaching it directly to an opening in the receiver.

Another important feature of the invention is that the surrounding protective casing is preferably constructed in the form of a substantially cylindrical tube that is merely cut to the desired size and provided with the viewing port or ports. If desired, one end of this tube may be reduced in diameter so tha-t it can be threaded to constitute a coupling portion. Thus, in this preferred form, the outer protective member of the indicator is of integral construction, merely shaped to thesdesired contours so that sealing problems involved in joining two or more pieces to make a single protective memberare avoided.

Other features and advantages of the inventioirwillbe apparent from the following description ofcertainembodiments thereof takeniin conjunction with the accompanying drawings. Of the drawings:

Figure 1 is a side elevational view of one embodiment of the invention;

Figure 2 is a sectional elevational viewtaken substantially along line 2-2 of Figure -1;

Figure 3 is an end elevational view of the indicator of Figure l taken from the left-handend of Figure 1;

Figure .4 is a View similar to Figure 2, but showing a modification of the indicator;

Figure 5 is anenlarged detailed viewin sectionalvelevation and partially broken away for clarity 'ofillustration ofa portion of the transparent tube, protective housing, gasket and. associated structure. j vThe embodiment of the invention shown in Figures comprises a protective member or housing containing bppositely located viewing ports 10aV andcoiitaiuiug ,a

`A2,817,309 Patented Dec. 24, 1957 "ice transparent tube 11 preferably made of glass. The transparent tube 11 is aligned with the viewing ports or openings 10a so that the'contentsof the tube are easily viewed through the openings. v

The protective housing 10 in the embodiment shown iriv Figures 1-3 has one end 12 reduced and provided on its outer surface with threads 12a for attaching in the customary manner to a fluid line. Substantially` the remainder of the housing 10 has an internal bore 10b of generally cylindrical shape `andof substantially uniform diameter, with this bore extending through the end 10c of the housing 10 that is opposite to the reduced end 12. This end 12C of the housing may be similarly `provided with threads V10d for attaching toa fitting or, if desired, for attaching directly to the wall of a refrigerant receiver when the indicator is usedin its preferred environment in a refrigeration system.

As can be seen from the drawings, the protective housing 10 is substantially uniform in diameter in its internal bore 10b for almost the entire length of the housing. The reducedtend 12 of the housing is provided with its fluid passage bore 12b, which communicates with the interior of the transparent tube 11 and with the vinternal bore 10b beyond the tube 11 in order to provide iluid flow through the indicator.

The provision of the reduced end 12 of the housing results in a sloped internal shoulder 10e within the housing. However, as can be seen from Figure 2, the entire housing is of integral construction with a uniform, substantially cylindrical, internal bore 10b 4from. the extreme end 10c of the housing to the sloped shoulder 10e.

Means are provided for making a fluid-tight sealbetween the end portions of the transparent tube 11 and the housing 10. In the embodiment shown, this seal is provided by means of a pair of annular gaskets 13 and 14, with each gasket bearing against an end surface 11a of the transparent tube. The gasket 14 is retained in position against its end of the transparent tube 11 by means of a metal retainer 1S. This metal retainer has sides of generally L-shaped cross-section with an annular planar side 15a of this retainer bearing against the side of the gasket opposite to the tube edge 11a and a substantially cylindrical internal flange 15b `of the retainer bearing against the inner surface of the gasket14. This inner flange 15b is substantially concentric with the transparent tube 11 and has an louter diameter slightly less than the internal diameter of the tube 11. The planar portion 15a of the retainer bears against the sloped internal shoulder 10e lof the protective housing 10.

At the opposite end of the tube 11 and bearing similarly against the other gasket is a second metal retainer 16. This second metal retainer has a planar portion 16a similar to the planar portion 15a and a ange 16b similar to and substantially aligned with the flange 15b on the opposite retainer.

Bearing against the. retainer 16 is a helical compression spring 17 located within the internal bore 10b of the housing 10 between the retainer 16 and the end 10c of the housing. This spring, which is normally substantially coaxial with the housing 10, is held in place and under compression by means of an annular metal retainer 18 fitted within the end 10c of the housing 10. This metal retainer is press t so as to be retained within the housing 10 and to apply a compressive force on the spring 17. Thus, in actual practice, where the housing 10 and retainer 18 are made of metal such as brass, the retainer 18 has an outer diameter slightly larger than the internal diameter of the end 10c of the housing before the retainer is pressed into place. In one embodiment, this retainer 18 had an external diameter 0.605 inch greater than the internal diameter of the end 10c of the housing 10 before the retainer was pressed into place. Here, the parts were .the transparent f tubel `v.brass `and thisdierence vwas suicient to .retain .they retainer 18 firmly within the housing.

The central portion g yof the housing 10 surrounding 11v is preferably lmade of polygonal .shape-1in transverse 'cross-section.. 'Ihus?, in thefemb'odi- ,'mntshown, this portion is hexagonal 'with alll of the sides of the hexagon being equal. This' polygonal,;cross :sectional shapeis preferably providedso'aswto accoml-modate aHwrench by'means of which theiindicator'may jbe h eld,^;turned, or otherwise manipulated' during the installation of, the indicator.C f.. .l y, f `The .oppositely located ports or viewingiopenings l10a vare each' preferably located substantially completely within onesideiof the vcentral portion 10g" of the housing.` Thus, as is-shown inthe drawings, each viewing opening 10a is .located subs'tantiallytentirely` between two adjacent angles *ofthepolygon. Thisfstructureis used so that. vthe cutting Iaway Eof .the indicator toprovide the viewing 'openings or .windowswill not .change the'shape of the polygon and so that a wrench may .stillgrasp firmlyf the portion 10g of the indicator. I Thus, if desired; the jaws of the wrench vmay actually span the opening'sla and permit full force ,and leverage to be exerted'on the indicator.

- Inthe construction as illustrated, the Windows 10a have lthe end surfaces 10h sloped generally-inwardly'toward :each-other. .'This construction produces ashadowl box electso that not only does the viewing opening appear to be larger than it actually is vbut it alsoidirects'the line of sight of the person looking through the'opening toward the transparent tube'11 andtoward the opposite viewing :opening yon the other side of the indicator. In addition, .this sloped construction strengthens the housing in the .tareas adjacent the ends of the windows as it is not necessary to remove as much metal at these ends as would `ordnarily be required if the sloped construction was not use In the embodiment shown in Figures 1-3 inclusive, a single spring 17 applies compressive force on both gaskets 413 and 14 to provide the sealing pressure. Thus, the `spring acts directly on the first gasket 13 through the re* tainer 16 while the spring acts on the second gasket 14 .through the transparent tube 11. Although only one spring is used, the entire spring pressure is applied substantially equally to both gaskets 13 and 14.

The gaskets 13 and 14 not only provide sealing pressure against the ends of the transparent tube 11, but also resiliently lock the transparent tube 11 in place spaced from the internal surface of the housing 10. Each gasket also spaces itscorresponding retaining member 15 and 16 away rom the internal surface of the rhousing 10. The manner in which this is accomplished is shown most clearly in the enlarged detailed sectional view of Figure 5. Thus, as is shown here, spring pressure on a representative gasket 13 causes one portion 13a of the gasket to be eX- truded a short distance between the outer surface of the transparent tube 11 and the inner surface of the housing 10. A second portion 13b of the gasket is similarly eX- truded a short distance between the inner surface of the transparent tube 11 and the outer surface of the ilange 16b of the retainer 16. A third portion 13C of the gasket is partially extruded between the outer edge of the retainer portion 16a and the inner surface of the housing 10.

AY117 is provided that is similar tothe rst spring 17, and

Thus, the two gasket portions 13a and 13b lock the transi parent tube firmly in position. Similarly, the third ex truded portion 13o of the gasket locks the retainer 16 lirmly yet yieldingly in position. The opposite gasket 14 functions similarly with respect to the transparent tube and its retainer 15.

In the embodiment shown in Figure 4, the protective housing 110 is provided with opposite openings l10n and a threaded end part 110e similar to corresponding parts of the rst embodiment. In the second embodiment, however, the housing 110 is of substantially uniform linternal diameter from end to end so as to have a substantially uniform bore. Also, in this embodiment a second spring this second spring is heldin position by an annular retainer 118 similar to the retainer 18. In this second embodiment, the gaskets 13 and 14 and the retainers 15 and 16 are substantially the same in construction and function as are the same parts in the iirst embodiment. In this second embodimentwbothends of the housing which are of substantially uniform shape and diameter are provided with threads `dV-that are similar to the threads 10d of the embodmentpf `Figures 1-3.

As was pointed outabove, the indicator of this invenf tion,4 has a.number offadvantages not found in prior indicators. Thus, the new indicator is quite compact and requires a smaller'number of fittings to attach it into the fluid line. Also, the indicator is much less expensive to make as the shape and configuration of the various parts are kept quite simple. One principal feature of the invention is providingithe press fit retainer-atene or both=ends asexempliiied by lthe retainer 18 in orderto hold the parts assembled. This is not onlyl advantageous .from an expense standpoint but also makes assembling very easy. Thus, in theembodiment shown 4in lFigures l-3, it is only necessary in assembling to position in the housing 10 in the order named the retainer 15, 'gasket 14, the transparent Vtube 11,y gasket 13, retainer 16,"and.spring 17 and then press into position the press tit retaining washer 18. When this procedurevistfollowed,the. parts more or less automatically assume the proper relationship as shown most clearly inFigure.2.` f. In the 'embodiment shown in Figure 4, substantiallyy the same procedure may be followed except here one' of the retainers 18 or 118 may be iirst pressed in position and the other elements inserted in the proper orderin -th'e manner. described in connection with the tirstfernbodiment.;r i

Oneirnportant-featre of this invention is that neither of the gaskets 213 011-14 seals against shoulders or other inwardlyprojec'ting surfaces.Instead, both gaskets seal primarilyfagain'st the .cylindrical portion of the' inner surface 10b'of the housing .10."k Thus, there is novpossibility of eitherfgasket shifting awayl from the sealing surface due Ito yielding lof the gasket material or due to differences. of coeiiicients 'of thermal expansion of the parts of the indicator as the-sealing surfaces may be actually. the full internal surface of the housing, not including, of course, the reduced end 12 of the first embodiment. l v y Although the press iitted end-retainers 18 or 118 will retain `their positionindetinitely, it is actually only necessary that'itheyzretain their position long enough for the indicator to be fitted into the iluid line.

Having. described'my Vinvention as related to the embodiments'shownin the accompanying drawings, it is my intention thatl the invention be not limited by any of the details of description, unless otherwise specified, but rather be construed broadly within its spirit and scope as set out in the accompanying claims. I claim:v .U

1. `An indicator conduitapparatus, comprising: a transparent tube; a' surrounding fprotective member within which the tube is located containing'a port through which the tube and contents are viewable; a sealing gasket at each rend o f the .tube making sealing contact with said end and withtlie adjacent inner Vsurface of the protective member; a pressure, applying member within the protec- -tive member urging the gaskets into said sealing contact wi'ththegtube, the protective member having an internal area of substantially uniform' diameter` extending from one end thereof and includingthose portions of the in'- 'terior occupied by the assembly ofl transparent tube, sealinggaskets 'and pressure applying member, the trans,- parent tube, sealing gaskets andpre'ssure ,applying memf ber being; insertable'into theprotective member through said `one 'end in `assembling the indicator;v and a separate retainingmember located at said 'one end 'for retaining said assembly in' plac.

animos 2. The apparatus of claim 1 wherein the retaining member comprises a closure member retained within said opening and having a fluid passage therethrough.

3. The apparatus of claim 1 wherein said pressure applying member comprises yieldable resilient means.

4. The apparatus of ciaim l wherein said retaining member comprises an annular washer press tted within said one end.

5. The apparatus of claim 1 wherein each gasket is located at an end edge of the tube and each gasket includes a rst portion extruded into the area between the tube and protective member and a second portion eX- truded around an inner edge of the tube, to lock the tube firmly yet yicldingly in place and maintain the tube out of contact with the protective member.

6. An indicator conduit apparatus, comprising: a transparent tube; a surrounding protective member within which the tube is located containing a port through which the tube and contents are viewable; a sealing gasket at each end edge of the tube making sealing contact with said edge and with the adjacent inner surface of the protective member; resilient means within the protective member urging the gaskets into said sealing contact with the tube, the protective member having an internal area of substantially uniform diameter extending from one end thereof and including those portions of the interior occupied by the assembly of transparent tube, sealing gaskets and pressure applying member, the transparent tube, sealing gaskets and pressure applying member being insertable into the protective member through said one end in assembling the indicator; and a closure member press fitted within said one end having a uid opening therethrough, for retaining said assembly in place.

7. An indicator conduit apparatus, comprising: a transparent tube; a surrounding protective member within which the tube is located containing a port through which the tube and contents are viewable; a sealing gasket at each end of the tube making sealing contact with said end and with the adjacent inner surface of the protective member; a pressure applying member within the protective member adjacent to one end thereof urging the gaskets into said sealing contact with the tube; and a closure member press tted within said one end having a uid opening therethrough, for retaining said assembly in place.

8. An indicator conduit apparatus, comprising: a transparent tube; a surrounding protective member within which the tube is located containing a port through which the tube and `contents are viewable; a sealing gasket at each end of the tube making sealing lcontact with said end and with the adjacent inner surface of the protective member; a pressure applying member Within the protective member urging the gaskets into said sealing contact with the tube, the protective member being a continuous metal tube of substantially uniform internal dameter throughout the length thereof that includes one end of the protective member and the space occupied by the transparent tube, a sealing gasket and a pressure applying member; and a separate retaining member located at said one end ttor retaining said assembly in place.

9. The apparatus of claim 8 wherein said retaining member -comprises an annular Washer press tted within said one end.

References Cited in the nie of this patent UNITED STATES PATENTS 2,136,261 Anderson Nov. 8, 1938 2,570,322 Christopher Oct. 9, 1951 2,725,844 Wittlin Dec. 6, 1955 2,744,487 Moore May 8, 1956 

